Reevaluating the Use of Models to Predict the Consequences of Habitat Loss and Fragmentation

Abstract

Because habitat fragmentation is severe and widespread, it has become the focus of much conservation research. One particularly popular approach involves the development of spatially explicit population models (SEPMs) that are used to evaluate the consequences of different habitat arrangements. These landscape models typically emphasize the importance of habitat clustering to the viability of threatened species or the preservation of biodiversity in general. We caution that the data requirements of these models may often be prohibitive, and argue that alternative approaches should be explored. As examples, we use data sets involving the patterns of colonization and extinction among frog species inhabiting ponds in Michigan, and among ladybird beetles occupying patches of vegetation at Mount St. Helens. We conclude that more attention should be given to the inferences that might be obtained directly from simple monitoring data and to the possibility of alternative explanations that have little to do with fragmentation.